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## org.jboss.util.collection
Class WeakValueHashMap

    java.lang.Object
      java.util.AbstractMap
          org.jboss.util.collection.WeakValueHashMap

All Implemented Interfaces:
  Map

public class WeakValueHashMap
extends AbstractMap
implements Map

This Map will remove entries when the value in the map has been cleaned from garbage collection

Version:
  `$Revision: 1.4 $`
Author:
  Bill Burke

Nested Class Summary

Nested classes inherited from class java.util.Map
`Map.Entry`

Constructor Summary
`WeakValueHashMap()` Constructs a new, empty `WeakHashMap` with the default initial capacity and the default load factor, which is `0.75`.
`WeakValueHashMap(int initialCapacity)` Constructs a new, empty `WeakHashMap` with the given initial capacity and the default load factor, which is `0.75`.
`WeakValueHashMap(int initialCapacity, float loadFactor)` Constructs a new, empty `WeakHashMap` with the given initial capacity and the given load factor.
`WeakValueHashMap(Map t)` Constructs a new `WeakHashMap` with the same mappings as the specified `Map`.

Method Summary
`void` | `clear()` Removes all mappings from this map.
`boolean` | `containsKey(Object key)` Returns `true` if this map contains a mapping for the specified key.
`Set` | `entrySet()`
`Object` | `get(Object key)` Returns the value to which this map maps the specified `key`.
`boolean` | `isEmpty()` Returns `true` if this map contains no key-value mappings.
`Object` | `put(Object key, Object value)` Updates this map so that the given `key` maps to the given `value`.
`Object` | `remove(Object key)` Removes the mapping for the given `key` from this map, if present.
`int` | `size()` Returns the number of key-value mappings in this map.

Methods inherited from class java.util.AbstractMap
`clone, containsValue, equals, hashCode, keySet, putAll, toString, values`

Methods inherited from class java.lang.Object
`finalize, getClass, notify, notifyAll, wait, wait, wait`

Methods inherited from interface java.util.Map
`containsValue, equals, hashCode, keySet, putAll, values`

Constructor Detail

### WeakValueHashMap

    public WeakValueHashMap(int initialCapacity,
                            float loadFactor)

  Constructs a new, empty `WeakHashMap` with the given initial capacity and the given load factor.

Parameters:
  `initialCapacity` - The initial capacity of the `WeakHashMap`
  `loadFactor` - The load factor of the `WeakHashMap`
Throws:
  `IllegalArgumentException` - If the initial capacity is less than zero, or if the load factor is nonpositive

### WeakValueHashMap

    public WeakValueHashMap(int initialCapacity)

  Constructs a new, empty `WeakHashMap` with the given initial capacity and the default load factor, which is `0.75`.

Parameters:
  `initialCapacity` - The initial capacity of the `WeakHashMap`
Throws:
  `IllegalArgumentException` - If the initial capacity is less than zero

### WeakValueHashMap

    public WeakValueHashMap()

  Constructs a new, empty `WeakHashMap` with the default initial capacity and the default load factor, which is `0.75`.

### WeakValueHashMap

    public WeakValueHashMap(Map t)

  Constructs a new `WeakHashMap` with the same mappings as the specified `Map`. The `WeakHashMap` is created with an initial capacity of twice the number of mappings in the specified map or 11 (whichever is greater), and a default load factor, which is `0.75`.

Parameters:
  `t` - the map whose mappings are to be placed in this map.
Since:
  1.3

Method Detail

### entrySet

    public Set entrySet()

  Specified by:
    `entrySet` in interface `Map`

### size

    public int size()

  Returns the number of key-value mappings in this map. Note: In contrast with most implementations of the `Map` interface, the time required by this operation is linear in the size of the map.

  Specified by:
    `size` in interface `Map`

### isEmpty

    public boolean isEmpty()

  Returns `true` if this map contains no key-value mappings.

  Specified by:
    `isEmpty` in interface `Map`

### containsKey

    public boolean containsKey(Object key)

  Returns `true` if this map contains a mapping for the specified key.

  Specified by:
    `containsKey` in interface `Map`
  Parameters:
    `key` - The key whose presence in this map is to be tested

### get

    public Object get(Object key)

  Returns the value to which this map maps the specified `key`. If this map does not contain a value for this key, then return `null`.

  Specified by:
    `get` in interface `Map`
  Parameters:
    `key` - The key whose associated value, if any, is to be returned

### put

    public Object put(Object key,
                      Object value)

  Updates this map so that the given `key` maps to the given `value`. If the map previously contained a mapping for `key` then that mapping is replaced and the previous value is returned.

  Specified by:
    `put` in interface `Map`
  Parameters:
    `key` - The key that is to be mapped to the given `value`
    `value` - The value to which the given `key` is to be mapped
  Returns:
    The previous value to which this key was mapped, or `null` if if there was no mapping for the key

### remove

    public Object remove(Object key)

  Removes the mapping for the given `key` from this map, if present.

  Specified by:
    `remove` in interface `Map`
  Parameters:
    `key` - The key whose mapping is to be removed
  Returns:
    The value to which this key was mapped, or `null` if there was no mapping for the key

### clear

    public void clear()

  Removes all mappings from this map.

  Specified by:
    `clear` in interface `Map`

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